Motion detection

Abstract

Motion detectors can include a housing defining a first cavity and an aperture extending through the housing. A circuit board can be disposed in the first cavity. An infrared sensor and a light sensor can be mounted on the circuit board. A lens can extend across the aperture. A wall can extend between the lens and the circuit board such that the wall, the lens, and the circuit board define a second cavity at least partially within the first cavity and the second cavity contains the infrared sensor and the light sensor.

What is claimed is: 
     
       1. A method, comprising:
 acquiring, by a computing system, a first plurality of samples of a first signal generated by an infrared sensor; 
 determining, by the computing system, that a first sample of the first plurality of samples is a first local minima or maxima of the first signal; 
 in response to the first sample being the first local minima or maxima, incrementing, by the computing system, a first value of a first counter; 
 in response to the first value of the first counter exceeding a first threshold within a first window of time, outputting, by the computing system, an indication of motion; 
 determining, by the computing system, that a second signal generated by a light sensor satisfies a criterion; and 
 in response to the second signal satisfying the criterion, increasing, by the computing system, the first threshold. 
 
     
     
       2. The method of  claim 1 , wherein:
 incrementing the first value of the first counter includes storing a first timestamp for the first sample in a queue; and 
 the first value of the first counter is based on a quantity of timestamps within the first window of time that are stored in the queue. 
 
     
     
       3. The method of  claim 2 , further comprising:
 determining, by the computing system, that a second sample of the first plurality of samples is a second local minima or maxima of the first signal; 
 in response to the second sample being the second local minima or maxima, storing, by the computing system, a second timestamp for the second sample in the queue; 
 determining, by the computing system, that the second timestamp is outside the first window of time; and 
 removing, by the computing system, the second timestamp from the queue based at least in part on the second timestamp being outside the first window of time. 
 
     
     
       4. The method of  claim 1 , further comprising:
 receiving, by the computing system, an input representing a changed sensitivity setting; and 
 adjusting, by the computing system, the first threshold based at least in part on the changed sensitivity setting. 
 
     
     
       5. The method of  claim 4 , wherein:
 receiving the input comprises receiving, by a radio frequency (RF) receiver, an RF signal encoded to represent the changed sensitivity setting; and 
 the method further comprises decoding, by the computing system, the RF signal to determine a modified value of the first threshold. 
 
     
     
       6. The method of  claim 1 , further comprising:
 operating the computing system in a first mode in which the computing system determines whether an amplitude of the first signal increases by more than an offset value; and 
 in response to the computing system determining that the amplitude of the first signal has increased by more than the offset value, operating the computing system in a second mode in which the computing system determines whether the first signal transitions from a positive slope to a negative slope. 
 
     
     
       7. The method of  claim 6 , wherein:
 determining that the amplitude of the first signal has increased by more than the offset value includes determining that a second sample of the first plurality of samples is more than the offset value greater than a preceding sample of the first plurality of samples; and 
 operating the computing system in the second mode includes setting the second sample as a positive extreme. 
 
     
     
       8. The method of  claim 7 , further comprising:
 determining that a third sample of the first plurality of samples is more than a threshold value below a first one of the first plurality of samples that is currently designated as the positive extreme; and 
 in response to the third sample being more than the threshold value below the first one of the first plurality of samples that is currently designated as the positive extreme:
 incrementing the first value of the first counter, and 
 operating the computing system in a third mode in which the computing system determines whether the first signal transitions from the negative slope to the positive slope. 
 
 
     
     
       9. The method of  claim 8 , wherein operating the computing system in the third mode comprises setting the third sample as a negative extreme, and the method further comprises:
 determining that a fourth sample of the first plurality of samples is more than the threshold value above a second one of the first plurality of samples that is currently designated as the negative extreme; and 
 in response to the fourth sample being more than the threshold value above the second one of the first plurality of samples that is currently designated as the negative extreme:
 incrementing the first value of the first counter, and 
 operating the computing system in the second mode. 
 
 
     
     
       10. The method of  claim 8 , wherein the offset value is a percentage of the threshold value. 
     
     
       11. The method of  claim 1 , wherein determining that the second signal satisfies the criterion includes:
 acquiring, by the computing system, a second plurality of samples of the second signal; 
 determining, by the computing system, that a second sample of the second plurality of samples corresponds to a second local minima or maxima of the second signal; 
 in response to the second sample corresponding to the second local minima or maxima, incrementing, by the computing system, a second value of a second counter; and 
 determining that the second signal satisfies the criterion based at least in part on the second value of the second counter exceeding a second threshold within a second window of time. 
 
     
     
       12. The method of  claim 11 , further comprising:
 generating, by the infrared sensor, the first signal; and 
 generating, by the light sensor, the second signal. 
 
     
     
       13. The method of  claim 1 , further comprising:
 generating, by the infrared sensor, the first signal; and 
 generating, by the light sensor, the second signal. 
 
     
     
       14. The method of  claim 1 , wherein outputting the indication of motion comprises:
 using a radio frequency (RF) transmitter to send, to a base station, an RF signal including a flag indicative of the motion. 
 
     
     
       15. A system, comprising:
 an infrared sensor configured to generate a first signal; 
 a light sensor configured to generate a second signal; 
 at least one processor; and 
 at least one non-transitory computer-readable medium encoded with instructions which, when executed by the at least one processor, cause the system to:
 acquire a first plurality of samples of the first signal; 
 determine that a first sample of the first plurality of samples is a first local minima or maxima of the first signal; 
 in response to the first sample being the first local minima or maxima, increment a first value of a first counter; 
 in response to the first value of the first counter exceeding a first threshold within a first window of time, output an indication of motion; 
 determine that the second signal satisfies a criterion; and 
 in response to the second signal satisfying the criterion, increase the first threshold. 
 
 
     
     
       16. The system of  claim 15 , wherein the at least one non-transitory computer-readable medium is further encoded with additional instructions which, when executed by the at least one processor, further cause the system to:
 increment the first value of the first counter at least in part by storing a first timestamp for the first sample in a queue; 
 wherein the first value of the first counter is based on a quantity of timestamps within the first window of time that are stored in the queue. 
 
     
     
       17. The system of  claim 16 , wherein the at least one non-transitory computer-readable medium is further encoded with additional instructions which, when executed by the at least one processor, further cause the system to:
 determine that a second sample of the first plurality of samples is a second local minima or maxima of the first signal; 
 in response to the second sample being the second local minima or maxima, store a second timestamp for the second sample in the queue; 
 determine that the second timestamp is outside the first window of time; and 
 remove the second timestamp from the queue based at least in part on the second timestamp being outside the first window of time. 
 
     
     
       18. The system of  claim 15 , wherein the at least one non-transitory computer-readable medium is further encoded with additional instructions which, when executed by the at least one processor, further cause the system to:
 receive an input representing a changed sensitivity setting; and 
 adjust the first threshold based at least in part on the changed sensitivity setting. 
 
     
     
       19. The system of  claim 18 , wherein the at least one non-transitory computer-readable medium is further encoded with additional instructions which, when executed by the at least one processor, further cause the system to:
 receive the input at least in part by using a radio frequency (RF) receiver to receive an RF signal encoded to represent the changed sensitivity setting; and 
 decode the RF signal to determine a modified value of the first threshold. 
 
     
     
       20. The system of  claim 15 , wherein the at least one non-transitory computer-readable medium is further encoded with additional instructions which, when executed by the at least one processor, further cause the system to:
 operate a first mode in which the system determines whether an amplitude of the first signal increases by more than an offset value; and 
 in response to determining that the amplitude of the first signal has increased by more than the offset value, operate in a second mode in which the system determines whether the first signal transitions from a positive slope to a negative slope. 
 
     
     
       21. The system of  claim 20 , wherein the at least one non-transitory computer-readable medium is further encoded with additional instructions which, when executed by the at least one processor, further cause the system to:
 determine that the amplitude of the first signal has increased by more than the offset value at least in part by determining that a second sample of the first plurality of samples is more than the offset value greater than a preceding sample of the first plurality of samples; and 
 operate in the second mode at least in part by setting the second sample as a positive extreme. 
 
     
     
       22. The system of  claim 21 , wherein the at least one non-transitory computer-readable medium is further encoded with additional instructions which, when executed by the at least one processor, further cause the system to:
 determine that a third sample of the first plurality of samples is more than a threshold value below a first one of the first plurality of samples that is currently designated as the positive extreme; and 
 in response to the third sample being more than the threshold value below the first one of the first plurality of samples that is currently designated as the positive extreme:
 incrementing the first value of the first counter, and 
 operate in a third mode in which the system determines whether the first signal transitions from the negative slope to the positive slope. 
 
 
     
     
       23. The system of  claim 22 , wherein the at least one non-transitory computer-readable medium is further encoded with additional instructions which, when executed by the at least one processor, further cause the system to:
 operate the system in the third mode at least in part by setting the third sample as a negative extreme; 
 determine that a fourth sample of the first plurality of samples is more than the threshold value above a second one of the first plurality of samples that is currently designated as the negative extreme; and 
 in response to the fourth sample being more than the threshold value above the second one of the first plurality of samples that is currently designated as the negative extreme:
 incrementing the first value of the first counter, and 
 operate the system in the second mode. 
 
 
     
     
       24. The system of  claim 22 , wherein the offset value is a percentage of the threshold value. 
     
     
       25. The system of  claim 15 , wherein the at least one non-transitory computer-readable medium is further encoded with additional instructions which, when executed by the at least one processor, further cause the system to determine that the second signal satisfies the criterion at least in part by:
 acquiring a second plurality of samples of the second signal; 
 determining that a second sample of the second plurality of samples corresponds to a second local minima or maxima of the second signal; 
 in response to the second sample corresponding to the second local minima or maxima, incrementing a second value of a second counter; and 
 determining that the second signal satisfies the criterion based at least in part on the second value of the second counter exceeding a second threshold within a second window of time. 
 
     
     
       26. The system of  claim 15 , wherein the at least one non-transitory computer-readable medium is further encoded with additional instructions which, when executed by the at least one processor, further cause the system to:
 output the indication of motion at least in part by using a radio frequency (RF) transmitter to send, to a base station, an RF signal including a flag indicative of the motion. 
 
     
     
       27. A system, comprising:
 a first infrared sensor configured to generate a first signal; 
 a second infrared sensor configured to generate a second signal; 
 at least one processor; and 
 at least one non-transitory computer-readable medium encoded with instructions which, when executed by the at least one processor, cause the system to:
 acquire a first plurality of samples of the first signal; 
 determine that a first sample of the first plurality of samples is a first local minima or maxima of the first signal; 
 in response to the first sample being the first local minima or maxima, increment a first value of a first counter; 
 acquire a second plurality of samples of the second signal; 
 determine that a second sample of the second plurality of samples is a second local minima or maxima of the second signal; 
 in response to the second sample being the second local minima or maxima, increment a second value of a second counter; and 
 in response to the first value of the first counter exceeding a first threshold within a first window of time and the second value of the second counter exceeding a second threshold within a second window of time, outputting an indication of motion. 
 
 
     
     
       28. The system of  claim 27 , wherein the first threshold and the second threshold are a same value. 
     
     
       29. The system of  claim 27 , wherein the first infrared sensor is configured and arranged to receive infrared radiation from a first portion of individual zones and the second infrared sensor is configured and arranged to receive infrared radiation from a second portion of the individual zones, the second portion being different than the first portion. 
     
     
       30. A method, comprising:
 acquiring, by a computing system, a first plurality of samples of a first signal generated by a first infrared sensor; 
 determining, by the computing system, that a first sample of the first plurality of samples is a first local minima or maxima of the first signal; 
 in response to the first sample being the first local minima or maxima, incrementing, by the computing system, a first value of a first counter; 
 acquiring, by the computing system, a second plurality of samples of a second signal generated by a second infrared sensor; 
 determining, by the computing system, that a second sample of the second plurality of samples is a second local minima or maxima of the second signal; 
 in response to the second sample being the second local minima or maxima, incrementing, by the computing system, a second value of a second counter; and 
 in response to the first value of the first counter exceeding a first threshold within a first window of time and the second value of the second counter exceeding a second threshold within a second window of time, outputting, by the computing system, an indication of motion. 
 
     
     
       31. The method of  claim 30 , wherein the first threshold and the second threshold are a same value. 
     
     
       32. The method of  claim 30 , wherein the first infrared sensor receives infrared radiation from a first portion of individual zones and the second infrared sensor receives infrared radiation form a second portion of the individual zones, the second portion being different than the first portion.